AUTHOR=Su Zhanqiang , Tong Panpan , Zhang Ling , Zhang Mengmeng , Wang Dong , Ma Kaiqi , Zhang Yi , Liu Yingyu , Xia Lining , Xie Jinxin 

TITLE=First Isolation and Molecular Characterization of blaCTX-M-121-Producing Escherichia coli O157:H7 From Cattle in Xinjiang, China

JOURNAL=Frontiers in Veterinary Science

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2021.574801

DOI=10.3389/fvets.2021.574801

ISSN=2297-1769

ABSTRACT=The bovine Escherichia coli O157:H7 is a major foodborne pathogen to cause severe bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome in humans. Cattle are recognized major reservoir and source of E. coli O157:H7. We investigated the antibiotic resistance, molecular profiles, and intrinsic relationship between 21 isolates of E. coli O157:H7 from cattle farms and slaughtering house in Xinjiang. Using pulsed-field gel electrophoresis (PFGE) molecular typing, 2 types of PFGE were revealed through cluster analysis, including clusters Ⅰ and Ⅱ, with 66% and 100% similarity of PFGE spectra between 21 isolates. We also detected that 18 isolates (86%) carried at least one virulence gene, 16 isolates (76%) carried the eae gene, and 7 (33%) carried the stx1+stx2+eae+hly+tccp genes. Eighteen isolates were susceptible to antibiotics. Three isolates were resistant to antibiotics, and 2 were multi-drug resistant. One of the 2 multi-drug resistant isolates detectably carried the blaCTX-M-121 gene. This is the first finding of the blaCTX-M-121 gene detected in E. coli O157:H7 isolated from cattle in Xinjiang. The blaCTX-M-121 gene is transferable between the bacterial strains via plasmid transmission. The results indicated that E. coli O157:H7 may have undergone clonal propagation in cattle population and cross-regional transmission in Xinjiang China.